I am unaware of others' objections to using N-1 as the denominator of sample
variance to eliminate bias in the estimation of population variance, but I
can note one "fly in the ointment." Unbiasedness is defined on the expected
value (mean) of the sampling distribution, not the median, and the
di
Claudia Stanny wrote:
I will also confirm John Kulig's comment that while the variance (computed
using N-1) is an unbiased estimator of the population variance, the
square
root of the variance (SD computed using N-1) is _not_ and unbiased
estimator of the population SD. I've forgotten the ma
Tipsters: I found more information on the N-1 issue. Here is the _logic_ of
"N-1". Quotes are from Toothaker's "Introductory Statistics", 1996, edition 2,
Brooks/Cole (note: X-bar = mean of a sample).
Take the top half of the variance formula: ADD (X - Mu)^2. Since we do not know
Mu, we substi
Michael Quanty asks:
>
>Why is 1 the magic number? I see how it makes more radical corrections for
>smaller sample sizes. But was it chosen for a theoretical or practical
>considerations.
>
The intuitive explanation is that the variance is computed on the
deviations of scores around the mean, w
Why is 1 the magic number? I see how it makes more radical corrections for
smaller sample sizes. But was it chosen for a theoretical or practical
considerations.
Michael S: Don't even think about referring me to Three Dog Night.
Michael B. Quanty, Ph.D.
Psychology Professor
Senior Institutiona
